英语词源字典 - 在线词源网站

thermosphere (n.)[thermosphere 词源字典]: 1924, from thermo- + sphere.[thermosphere etymology, thermosphere origin, 英语词源]
thermostat (n.): automatic instrument for regulating temperature, 1831, from thermo- + -stat.
Theropoda (n.): order of dinosaurs, Modern Latin, from Greek elements ther- "beast" + podos genitive of pous "foot," from PIE root *ped- (1) "a foot" (see foot (n.)). So called because the structure of the feet resembled quadrupeds rather than birds. Related: Theropod.
thesaurus (n.): 1823, "treasury, storehouse," from Latin thesaurus "treasury, a hoard, a treasure, something laid up," figuratively "repository, collection," from Greek thesauros "a treasure, treasury, storehouse, chest," from root of tithenai "to put, to place" (see theme). The meaning "encyclopedia filled with information" is from 1840, but existed earlier as thesaurarie (1590s), used as a title by early dictionary compilers, on the notion of thesaurus verborum "a treasury of words." Meaning "collection of words arranged according to sense" is first attested 1852 in Roget's title. Thesaurer is attested in Middle English for "treasurer" and thesaur "treasure" was in use 15c.-16c.
these (pron.): Old English þæs, variant of þas (which became those and took the role of plural of that), nominative and accusative plural of þes, þeos, þis "this" (see this). Differentiation of these and those is from late 13c. OED begins its long entry with the warning, "This word has a complicated history."
Theseus: legendary hero-king of Athens; the name is of uncertain origin.
thesis (n.): late 14c., "unaccented syllable or note," from Latin thesis "unaccented syllable in poetry," later (and more correctly) "stressed part of a metrical foot," from Greek thesis "a proposition," also "downbeat" (in music), originally "a setting down, a placing, an arranging; position, situation," from root of tithenai "to place, put, set," from PIE root *dhe- "to set, to put" (see factitious). Sense in logic of "a formulation in advance of a proposition to be proved" is first recorded 1570s; that of "dissertation presented by a candidate for a university degree" is from 1650s.
thespian (adj.): 1670s, "of or pertaining to tragedy or dramatic acting," from Greek Thespis, semi-legendary 6c. B.C.E. poet of Icaria in Attica, often called the Father of Greek Tragedy. The literal meaning of the name is "inspired by the gods."
thespian (n.): "an actor," 1827, from thespian (adj.). Short form thesp is attested from 1962.
Thessaly: district south of Macedonia and east of Epirus, from Greek Thessalia (Attic Thettalia), an Illyrian name of unknown origin. Related: Thessalian. The city of Thessalonika on the Thermaic Gulf was ancient Therme, renamed when rebuilt by the Macedonian king Cassander, son of Antipater, and named in honor of his wife, Thessalonica, half-sister of Alexander the Great, whose name contains the region name and Greek nike "victory." The adjectival form of it is Thessalonian Related: Thessalonians.
theta (n.): eighth letter of the Greek alphabet; in ancient Greece, from Hebrew teth; originally an aspirated -t- (see th). Written on ballots to indicate a vote for a sentence of "death" (thanatos), hence occasional allusive use for "death."
Thetis: name of a sea goddess in Greek mythology, mother of Achilles by Peleus. Since Roman times, sometimes, in poetry, "the sea personified."
theurgy (n.): 1560s, "white magic," from Latin theurgia, from Greek theourgia "sorcery," from theos (genitive theou) "a god" (see theo-) + -ergos "working" (see organ). From 1858 as "the working of divine forces in human affairs." Related: Theurgical.
thew (n.): Old English þeaw "usage, custom, habit;" see thews.
thews (n.): Old English þeawes "customs, habit, manners; morals, conduct, disposition, personal qualities," plural of þeaw "habit, custom," from Proto-Germanic *thawaz (cognates: Old Saxon thau "usage, custom, habit," Old High German thau "discipline"). According to OED, with no certain cognates outside West Germanic and of unknown origin, but Watkins traces it to PIE root *teue- (1) "to pay attention." Meaning "bodily powers or parts indicating strength, good physique" is attested from 1560s, from notion of "good qualities." Acquired a sense of "muscular development" when it was revived by Scott (1818).
they (pron.): c. 1200, from a Scandinavian source (Old Norse þeir, Old Danish, Old Swedish þer, þair), originally masculine plural demonstrative pronoun, from Proto-Germanic *thai, nominative plural pronoun, from PIE *to-, demonstrative pronoun (see that). Gradually replaced Old English hi, hie, plurals of he, heo "she," hit "it" by c. 1400. Colloquial use for "anonymous people in authority" is attested from 1886. They say for "it is said" is in Milton.
The most important importation of this kind [from Scandinavian to English] was that of the pronomial forms they, them and their, which entered readily into the system of English pronouns beginning with the same sound (the, that, this) and were felt to be more distinct than the old native forms which they supplanted. Indeed these were liable to constant confusion with some forms of the singular number (he, him, her) after the vowels has become obscured, so that he and hie, him and heom, her (hire) and heora could no longer be kept easily apart. [Jespersen, "Growth and Structure of the English Language"]
thiamin (n.): also thiamine, alternative name for vitamin B1, 1937, coined by U.S. chemist Dr. Robert R. Williams (1886-1965) from thio-, indicating the presence of sulfur, comb. form of Greek theion "sulfur," + amine, indicating the amino group. Or the second element might be from vitamin.
thick (adj.): Old English þicce "dense, viscous, solid, stiff; numerous, abundant; deep," also as an adverb, "thickly, closely, often, frequently," from Proto-Germanic *thiku- (cognates: Old Saxon thikki, Old High German dicchi, German dick, Old Norse þykkr, Old Frisian thikke), from PIE *tegu- "thick" (cognates: Gaelic tiugh). Secondary Old English sense of "close together" is preserved in thickset and proverbial phrase thick as thieves (1833). Meaning "stupid" is first recorded 1590s. Related: Thickly.

As a noun, "the thick part" (of anything), from mid-13c. Phrase through thick and thin, indicating rough or smooth going, hence "unwaveringly," is in Chaucer (late 14c.); thick-skinned is attested from 1540s; in figurative sense from c. 1600. To be in the thick of some action, etc., "to be at the most intense moment" is from 1680s, from a Middle English noun sense.
thicken (v.): late 14c. (transitive), 1590s (intransitive), from thick + -en (1). Related: Thickened; thickening. An earlier verb was Middle English thick, Old English þiccian "to thicken, to crowd together."
thickening (n.): "substance used to thicken something," 1839, verbal noun from thicken.